A teenager was decapitated and his head thrown into a police station entrance in a shocking incident in the southern Indian state of Tamil Nadu. Police suspect the 17-year-old was hacked to death during local gang infighting.

Footage from the police station CCTV camera shows two men on a motorbike hurling the severed head into the entrance and driving away at about 8pm local time on Wednesday, 10 May. The incident took place in the Cuddalore district.

Police later found the headless corpse in a nearby lake and identified the victim as Swethan, who goes by a single name.

Three men aged between 20 and 24 were arrested on Thursday, while the main culprit is said to be at large. A post-mortem of the Swethan's body is still underway.

"Investigation is on. Vinod is the main accused in the case. The gang's suspicion that the youngster informed the police about their crimes appears to be the motive," a senior police officer, Rajiv Ranjan, told the Indian broadcaster NDTV.

Initial reports suggest the victim had told the police about the gang's criminal activities in the area, angering the members of the clan. The group of men are thought to be involved in low-level crimes like robbery. The brutal incident has shocked the local community.

Warning: Video below contains graphic images